Soil contamination by metals and radionuclides in missile-affected areas: radiological risk assessment and phytotoxic effects on wheat plants.

Military conflicts constitute an increasingly important yet still insufficiently quantified source of environmental contamination in agricultural ecosystems. This study investigated soils affected by missile strikes during the Russian aggression in Ukraine, with particular emphasis on heavy metal accumulation, radionuclide occurrence, and associated phytotoxic effects on wheat (Triticum aestivum L.). Geochemical analyses using X-ray fluorescence spectroscopy revealed pronounced enrichment of Pb, Zn, Cu, Cr, Ni, and Mn in crater soils, frequently exceeding local geochemical background levels and environmental guideline thresholds. Elevated activity concentrations of ^137Cs were additionally detected, indicating contamination associated with explosive materials and projectile components. Despite locally increased radionuclide levels, the calculated radiological indices demonstrated that the investigated soils do not currently pose a significant radiological hazard to human health. The contamination was accompanied by soil acidification, compaction, and degradation of physical structure, suggesting long-term disturbance of soil functioning in affected agricultural areas. Among the detected contaminants, Pb was consistently enriched in crater soils and was therefore selected as a representative model toxicant to investigate the biological mechanisms linking field-observed contamination to crop responses under controlled conditions. Hydroponic experiments demonstrated that Pb exposure induced a clear, dose-dependent inhibition of plant growth, biomass accumulation, and stress tolerance indices, whereas low Pb concentrations produced a slight hormetic response. Anatomical analyses of wheat roots revealed substantial structural reorganisation, including reduced stele and xylem development, enhanced cortical porosity, increased endodermal suberisation and lignification, and reduced vessel diameter, potentially limiting water and nutrient transport. Strong correlations between Pb concentration, anatomical modifications, and morphophysiological responses indicate that root structural disruption represents a major mechanism of toxicity. The results demonstrate that missile-derived contamination may significantly affect soil quality and crop performance even outside active combat zones. Furthermore, the study highlights the usefulness of root anatomical traits as sensitive biomarkers for early detection of military-induced soil stress and provides new insight into the combined, radiological and mechanistic biological approaches for assessing post-conflict agricultural environments.